The atmospheric build up of greenhouse gases (GHGs) is a serious environmental issue. Globally, agricultural activities are an important source of anthropogenic GHGs contributing approximately 20% of the annual atmospheric increase. Management choices largely determine if agricultural soils will be a source, a sink, or will be neutral with respect to CO2 flux. The quality and quantity of pulse residues varies substantially from that of cereals, thus introducing pulses into cereal-based cropping systems could influence the soil CO2 flux balance. Legumes are thought to stimulate soil-emitted N2O, although some recent research on pulse crops does not appear to support this understanding. Pulse crops have different pesticide and fertilizer requirements than cereals and including them into a cropping system may also influence overall fossil fuel inputs. The final GHG outcome of introducing pulses into cropping systems is currently unclear. This paper will briefly review the available literature and discuss the potential impact that pulse crops may have on the net flux of CO2, N2O, and CH4 and overall energy inputs of cropping systems in the northern great plains of North America. Several case studies will be presented.